That men go to bed with XYZ (the character from one of her movies) but they always wake up with her. I could see Clark having worries about Lois wanting to sleep with Superman and waking up with Clark.
Virginia, that reminds me of a She-Hulk comic I read where a man went to bed with She-Hulk but was shocked to wake up with Jennifer Walters (her normal, non-green form). Bit more of an extreme case.